Need new muffler for 318, looking for quiet, what are my options?

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67CBodyGuy

67CBodyGuy

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My car with 318 has single exhuast, pipes are 2.25 inch, muffler is 2 ft long, 1 ft wide, 4.5 inches high. Muffler is shot.

I'm not looking for any sort of "performance" sound. I just want quiet. I have no idea if going to 2.5 inch pipes will give better flow, but might give different (or better?) muffler choices. Seem to be lots of generic mufflers available from rock auto, I just have to choose pipe size, then muffler size.

Some muffler's have 2-in / 1-out. How would that work instead of having a cross-over pipe?
 
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Nobody here can tell you which brand will sounds the best to YOU.

2 1/4 should serve you well enough with a 318. I have a 360, and a 2 1/2 exhaust system.
Ignore anyone who mentions backpressure, they are retarded. In fact, you should cut them out of your life completely, you don't need that kind of negativity in your life.
Look up exhaust scavenging, do some serious reading on the subject. There are online calculators to figure out the range of exhaust diameters.
H-pipes sound American.

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X-pipes make your car sound like gay eurotrash.
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Joking aside, go on YouLube and search for different types of exhaust on engine displacements between 273-340.
 

67CBodyGuy said:
My car with 318 has single exhuast, pipes are 2.25 inch, muffler is 2 ft long, 1 ft wide, 4.5 inches high. Muffler is shot.

I'm not looking for any sort of "performance" sound. I just want quiet. I have no idea if going to 2.5 inch pipes will give better flow, but might give different (or better?) muffler choices. Seem to be lots of generic mufflers available from rock auto, I just have to choose pipe size, then muffler size.

Some muffler's have 2-in / 1-out. How would that work instead of having a cross-over pipe?
Click to expand...
Based on a 24" long case and your measurements, a walker wlk-27259 or wlk-18929 should meet your needs. Look at your pipe offsets and overall length to include the muffler pipes.

wlk-27259

wlk-18929
 
Pricey but Accurate exhaust should have close to what was on it new. I had the 2.5 header etc system on my Swinger but went stock with chrome tips at some point, its worth it if its a street driver. It fits the car best etc.
 
The muffler on the car now (67 Monaco, so a C-body) likely dates to 1987 (car wasn't driven, stored inside between 2000 - 2022). I don't know where I'd find the size/dimensions for the factory muffler.

I've downloaded a 400+ page PDF file from Walker. I can scan down the tables and find sizes that are close. I'd prefer stainless, and I think I'd prefer their QuietFlow and not the SoundFX.

Here's a question: Is muffling proportional to the muffler size (or internal volume) ? I have room for a larger muffler. I also know (or I think) that hanger design/construction can play a huge role in cabin noise.
 
67CBodyGuy said:
The muffler on the car now (67 Monaco, so a C-body) likely dates to 1987 (car wasn't driven, stored inside between 2000 - 2022). I don't know where I'd find the size/dimensions for the factory muffler.

I've downloaded a 400+ page PDF file from Walker. I can scan down the tables and find sizes that are close. I'd prefer stainless, and I think I'd prefer their QuietFlow and not the SoundFX.

Here's a question: Is muffling proportional to the muffler size (or internal volume) ? I have room for a larger muffler. I also know (or I think) that hanger design/construction can play a huge role in cabin noise.
Click to expand...
Generally, apples to apples, the larger the case, the greater the noise reduction. Also helps in general for it to be a replacement for some oem application versus universal, and a smaller outlet than inlet. A quiet flow should last longer but walkers are good, affordable mufflers.
 
If you go to the Flowmaster site they list all their mufflers from quiet to loud, so you can pick one that on the quiet side. Probably not you cheapest option though
 
MV8 said:
Generally, apples to apples, the larger the case, the greater the noise reduction. Also helps in general for it to be a replacement for some oem application versus universal, and a smaller outlet than inlet. A quiet flow should last longer but walkers are good, affordable mufflers.
Click to expand...

In the charts I was seeing a lot of mufflers where the outlet WAS smaller than the inlet. Like 2.25 in / 2.0 out. I thought that if anything, you wanted the downstream path to expand because as the exhaust gasses cool it will expand. Or I thought that was the theory. I can't find a 4.5 x 11 x 23 muffler. I'd have to accept a 20 length instead. Or move up to 5.5 x 11. But I'm confused about seeing the smaller outlet (like 2.0). Is that really ok? Back pressure? Or should I avoid that?
 
I put Dynomax Super Turbos on my Swinger but it's just a stock 318 2 barrel with some home made dual exhaust. The old mufflers were rotted and these were the right size and available at a local Farm store. They are pretty quiet at idle.
 
MV8 said:
Generally, apples to apples, the larger the case, the greater the noise reduction. Also helps in general for it to be a replacement for some oem application versus universal, and a smaller outlet than inlet. A quiet flow should last longer but walkers are good, affordable mufflers.
Click to expand...
I have 2 exhaust systems for my Hardtop R/B 500 Stroker. 1 all 3"with X pipe and racing mufflers. Another with 3"' H pipe with 3" Chevy suburban mufflers for quieter cruising.

Walker Exhaust 21054 Walker Quiet-Flow 3 Mufflers | Summit Racing
 
toolmanmike said:
I put Dynomax Super Turbos on my Swinger but it's just a stock 318 2 barrel with some home made dual exhaust. The old mufflers were rotted and these were the right size and available at a local Farm store. They are pretty quiet at idle.
Click to expand...

Were they the 17662 ? What size are your pipes?

​

 
67CBodyGuy said:
In the charts I was seeing a lot of mufflers where the outlet WAS smaller than the inlet. Like 2.25 in / 2.0 out. I thought that if anything, you wanted the downstream path to expand because as the exhaust gasses cool it will expand. Or I thought that was the theory. I can't find a 4.5 x 11 x 23 muffler. I'd have to accept a 20 length instead. Or move up to 5.5 x 11. But I'm confused about seeing the smaller outlet (like 2.0). Is that really ok? Back pressure? Or should I avoid that?
Click to expand...
Many oems have stepped it down. Pressure is greater the closer it is to the engine. You seem to be getting away from a quiet muffler that fits the existing pipes.
 
67CBodyGuy said:
Were they the 17662 ? What size are your pipes?

​

Click to expand...
Heck if I know what number. That was 10 years ago. They are 2 1/4 I believe. The prev. owner owns a welding shop and he split the original single exhaust and fashioned duals using the original single pipe on the left.
 
67CBodyGuy said:
Yes.

If I keep it single, should I at least have a 2.5 pipe instead of 2.25 ?
Click to expand...
2.5 would help the engine breath a bit more up high in the RPMS. I think the walker Quiet flow is a good choice. Yon can also add a glass pack if you have a long straight area in the exhaust, usually near the exhaust tip is a good location.
 
dano said:
2.5 would help the engine breath a bit more up high in the RPMS. I think the walker Quiet flow is a good choice. Yon can also add a glass pack if you have a long straight area in the exhaust, usually near the exhaust tip is a good location.
Click to expand...
Yes, would probably take out any drone.
 
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